1. Field of the Invention
The present invention relates to battery charging technology. More particularly, the present invention relates to a method and apparatus that provides charging information to optimize the charging efficiency when a portable terminal changes its battery using a solar cell.
2. Description of the Related Art
With the development of mobile communication technology, portable terminals now provide a variety of optional functions, such an MP3 player function, a mobile broadcast receiving function, a moving image playback function, a camera function, etc. A significant aspect of operating portable terminals providing such various functions is power usage, particularly so as not to deplete the batteries so as to hinder their use. In recent years, portable terminals have attempted to charge their battery by utilizing solar energy in order to overcome the limitation regarding the battery use time.
Solar energy technology uses the Sun's energy and light to provide heat and light. For example, a solar heating technology refers to a technology that heats water using the Sun's solar energy through housings that transfer heat to the water. A sunlight use technology also refers to a technology that converts the Sun's light to the electricity and drives a variety of devices, etc., using the electricity. Solar energy is an inexhaustible and harmless energy resource. That is, solar energy does not cause pollution to generate electricity, such as air pollution, noise pollution, greenhouse gases, vibration, etc. Solar energy can be used in virtually any area where the sunlight falls. Solar energy technology has recently been applied to portable terminals to charge their battery with solar energy. However, portable terminals adapted to use a conventional solar energy charging method have many disadvantages in that their battery charging efficiency depends on the weather conditions, time, and the sunlight intensity, and thus can be so low that a user cannot depend on being able to charge the battery.
For example, although the portable terminals utilizing a solar energy charging process for the same amount of time can have very different levels of charge, particularly if the portable terminals are exposed to different external environmental conditions, such as different weather conditions and different intensities of sunlight. The result is that as the batteries can be charged with different amounts of charge even to the same device, with such dependence on external conditions the users cannot know whether the portable terminals are charging the battery with an optimal efficiency, or how long it would take on a given day to charge the battery back to maximum power, for example.